Holocene palaeo-geographical evolution of the Sele River coastal plain (Southern Italy): New morpho-sedimentary data from the Paestum area

The Sele River Plain is hosted in a graben along the Tyrrhenian margin of the southern Apennine Chain and is formed of both displaced (Early and Middle Pleistocene) and undisturbed (Late Pleistocene and Holocene) sedimentary units. The strip that was accreted to the Plain during the Holocene high stand is characterized by beach-dune ridges whose sands interfinger –to the rear- with lagoonal and fluvio-palustrine deposits. The evolutionary trend was transgressive during the Early Holocene and progradational during the Mid-Late Holocene. In this work, we present new data about the Holocene evolution of the portion of the Plain in front and immediately north of the Poseidonia-Paestum archaeological area, where the knowledge has been improved by five new cores and by many collected archaeo-bio-tephrostratigraphical data. In the first area (Paestum area), due to a local rise of the ground (made of Late Pleistocene travertines) the Holocene transgression formed cliffs, while the second area (Laura area) was submerged. The tip of the travertine lobe was then cut by a sea cliff, whose correlative abrasion platform rests 7,5 m below the present s.l. The age of this stage can be inferred by the 14C dated mollusk remains (7.0 ky cal BP) of the beach deposits, found at the same depth in the Laura cores. In mid Holocene times the shoreline shifted seaward and a lagoonal environment – closed by the Laura sand ridge- was established (Fossa Lupata area). Age constraints for this stage are the Agnano M. Spina tephra (4.1 ky BP) and some archaeological remains of the VI cent. B.C. found within the upper part of the lagoonal clays. After this period, and mostly after the deposition of the 79 A.D. tephra, the shoreline shifted further seaward and an additional beach ridge formed, whereas the flat area of Fossa Lupata was rapidly aggraded and dried up.